This invention relates to an image processing apparatus having a function of enlarging and/or shrinking a source image with an arbitrary scale factor.
According to a conventional image processing technique, enlarging (or zooming) an image by z times or shrinking it by 1/z times was easily performed, if z is an integer. However, enlargement by n/m times (n and m are integers and n&gt;m&gt;o) or shrinkage by m/n times was difficult and required a long processing period with extremely complex software operations.
Heretofore, NN (Nearest Neighbor) method has been proposed to execute enlargement by n/m times and shrinkage by m/n times. However, it requires a large amount of complex calculations for each bit to be enlarged or shrinked. Therefore, even if the high-level software technique is employed, a long period of time must be spent.
Furthermore, image data is processed word by word in general. However, since the image data must be processed bit by bit in accordance with the NN method, processed bits must be packed word by word. This packing opeation also requires a long period of time.